What was Bezalel filled with the Spirit of God to do?
Bezalel was filled with the Spirit of God for workmanship—specifically, all manner of craftsmanship to devise curious works in gold, silver, and brass. He was given wisdom, understanding, and knowledge in workmanship, not spiritual things, enabling skilled design and execution.
Les explains that Moses told Israel the Lord had called Bezalel by name, the son of Uriah, son of Hur, of the tribe of Judah, and filled him with the Spirit of God. But the filling was not for spiritual things—it was for workmanship. Bezalel received knowledge of all manner of workmanship to devise curious work in gold, silver, and brass. Les stresses that God is concerned with every facet of our lives, physical and material as well as spiritual, and later notes that God filled these craftsmen with wisdom of heart to work all manner of work.
And Moses said unto the children of Israel, See, the LORD hath called by name Bezaleel the son of Uri, the son of Hur, of the tribe of Judah;
And he hath filled him with the spirit of God, in wisdom, in understanding, and in knowledge, and in all manner of workmanship;